Discussed this morning during the virtual Ubuntu Developer Summit was the Upstart road-map for during the Ubuntu 14.04 LTS cycle. There are two main features that Ubuntu developers want to bring to Upstart for 14.04: cgroup support and refined PTrace handling for Upstart service readiness.
Control groups support has been apart of the mainline kernel now since midway through the Linux 2.6 kernel series and Upstart developers now want cgroups for being able to limit resources on jobs. A cgroup stanza is to be added to Upstart for providing job resource management for resources like CPU, memory, and disk. Still though cgroups would be considered an optional Upstart feature although the Ubuntu kernel ships with the support by default. Cgroups support in Upstart has been talked about for a while (since at least H1'2012), but they hope it will happen for the Ubuntu Trusty cycle.
The other main feature they want to accomplish is refined ptrace handling that Upstart can use for service readiness of jobs. Lower priority but still desired is a time bridge and upstart user sessions on terminal log-ins.
If you're interested in more of the planned work on the event-based init daemon replacement, see the vUDS notes page and the Upstart Ideas page.